Treating metallic sulfids, &amp;c.



U. WEDGE.

TREATING METALLIC SULFIDS, 6m.

APPLICATION FILED JUNE 5,1913.

Patented. Jan. 25, 19 16.

2 SHEETS-SHEET I.

U. WEDGE.

TREATING METALLIC SULFIDS, (Sac. APPLICAflON FILED JUNE 5.1913.

2 SHEETS-SHEET 2.

LlfigfiQ, Patented Jan. 25, 1916.

pm snares PATENT onion UTLEY WEDGE, OF ARDMORE, PENNSYLVANIA.

. TREATING METALLIC SULFIDS, 8w.

Application filed June 5, 1913.

To all whom it may concern Be it known that I, UTLEY WEDGE, a citizen of the United States, residing in Ardmore, Pennsylvania, have invented certain Improvements in Treating Metallic Sulfids, &c., of which the following is a specification.

My invention relates to the treatment of compounds of sulfur and metal such as iron pyrites, pyrrhotite, chalcocite, bornite, chalcopyrite, pentlandite, argentite, stannite, zinc blend, etc., the object of my invention being to effect, in an economical way, the recovery of the metal and the practically complete elimination of the sulfur with the recovery of the latter also, if desired.

As in most cases the compound treated will be a sulfid I will for convenience in this specification refer to it as such, but it should be understood that this is only representative and is intended to include as well other sulfur compounds of metals or groups of metals.

In the accompanying drawings-Figure 1 is a verticallongitudinal section of a furnace adapted for the carrying out of my invention, and Fig. 2 is a vertical transverse section of the same.

I have found that the practically complete elimination of sulfur from a metallic sulfid can beeffected by subjecting said sulfid to the proper temperature in a reducing or practically neutral atmosphere while at the same time the metal can be oxidized if oxygen is present so combined, or in such form or in such limited volume, as to effect the oxidation of the metal without tending to promote the oxidation of the sulfur, and that, as part of a continuous process, the metallic oxid thus produced can be converted to metallic form.

For the purpose of properly describing my invention I have selected for illustration a furnace of the superposed hearth type although my invention is not limited to the use of such furnace.

When a furnace of the superposed hearth type is employed, the number of hearths may be varied without departing from my invention, the furnace shown in the drawing having nine hearths numbered consecutively from top to bottom and being also provided with a central rotating shaft 10 havin projecting rabble arms 11 which are inten ed to be provided with rabbles whereby'the material can be moved over each hearth and fed Specification of Letters Patent.

Patented J an. 25, 1916.

Serial No. 771,886.

downwardly from hearth to hearth through suitable drop passages 12 therein, furnaces of this type being well known. I

The furnace shown in the drawing is divided into three superposed zones the uppermost zone including hearths 1, 2 and 3, the intermediate zone including hearths 4, 5 and 6, and the lowermost zone including hearths 7, 8 and 9. The furnace should 'be capable of heating the sulfid to the proper temperature and maintaining it at such temperature and the upper zone of the furnace should present an atmosphere of the character previously described which will effect the elimination of the sulfur and the conversion of the metal to the oxid while the intermediate zone should be supplied with a reducing agent, gaseous, solid or liquid, such for instance as water gas, producer gas, hydrogen gas, finely divided coal or charcoal, or various hydrocarbons, such as paraflin oils, coal tar, pitch, etc., whereby the metallic oXid in its passage through said intermediate zone may be converted into the metallic form, such as spongy iron, if the sulfid of that metal is being treated. The lowermost zone of the furnace is intended as a gas pro- 'ducer, carbonaceous material being burned or distilled upon the hearths of said zone and the gases thus produced being conveyed to the upper and intermediate zones of the furnace.

By preference the furnace is constructed in the muffle form, that is to say, each of the hearths of the furnace is provided with a chamber 13 through which products of combustion from an outside generator may be caused to circulate either in a straight, sinu ous or a zigzag course.

In the present instance I have shown the heating chambers 13 as supplied from a flue 141 in the wall at one side of the furnace and as discharging into a flue 15 in the wall at 4 instance at 17in Fig. 2. The gas generated in the lower zone ofthe' furnace may, however, circulate in series through the upper zones, or through the chambers of either zone.

The furnace shown in the drawing has outlets from the chambers of the upper zone for the escape of the vaporized sulfur, the intermediate and upper zones and the chambers of said intermediate zone communicating with one another thruogh the drop passages 12.

In order to supply to the upper zone of the furnace oxygen in such form as to eifect the oxidation of the metal without tending to promote the oxidation of the sulfur, the preferable agent is steam which may be introduced, as for instance by means of pipes 18, into some or all of the chambers of said upper zone, the oxygen of thesteam, under the temperature conditions maintained in said upper zone, breaking up 1ts combination'with hydrogen and combining with the metal to form oxid, the presence of steam mingling with the other vapor in this zone which vaporization of sulfur, accompanied. by the reactions, takes place, Wlll, in they case of iron sulfid, range from about 1400 F'., to 1600 'F., although the effective temperatures Vary in the case of different metallic sulfids. Theoretically the range of temperature is wider than that stated but there are practical diflicu'lties which, in many cases, interfere with the proper conduct of the process at temperatures outside of these limits.

Preferably the sulfid before belng introduced into the upper zone of the furnace is preheated, so that the desired action may take place immediatelynupon its introduction into said upper zone. Such preheating should be effected without access of oxygen to the sulfid and may be accomplished in dif ferent ways I prefer to effect it, in case the furnace is of the muffle type, by means of the gases which have previously been used for heating the hearths of the furnace and this object I accomplish by providing above the upper zone ofthe furnace a preheating chamber 19 which feceives the gases from the flue 15,

said gases, after circulating through the chamber 19 in a straight, sinuous, or a zigzag course, being discharged through an out-- let 20 to a suitable stack. Extending vertically across the chamber 19 are a series of receptacles 21, preferably in the form of pipes of tile or other refractory material, these pipes receiving the granular sulfid from the roof of the furnace over which it may be distributed by suitable rabbles on the uppermost rabble arms 11. Each of the receptacles 21 is provided at its lower end with a valve 22 and said valves may be opened and closed at intervals by any suitable. means, such for instance as those described in my Letters Patent No. 842,736, dated January 29, 1907, or No. 890,543, dated June 8, 1908, fresh volumes of sulfur entering the receptacles as heated volumes are discharged therefrom. v-

The small amount of sulfid exposed to the air at the top of each receptacle does not reach an oxidizing temperature but the material in the lower portions of the receptacles, having been retained for some time therein, is heated to a temperature approaching the point where the reactions beginfwhen thesulfid is subjected to the furnace atmosphere. If the recovery of the sulfur is de- I sired the sulfur -vapor escaping from that zone ofthe furnace in which such vapor is produced may be subsequently treated for the, removal, separation or recovery of the sulfur.

The metal is discharged from the intermediate zone of the furnace into'an airtight receptacle 23 in order to prevent the reversion of the same into oxid by reason of the access of air thereto while it is in a heated condition, and in order to prevent the admission of air to those zones of the furnace in which the presence of oxygen, or its presence in undue volume, is to be avoided, the shaft 10 is luted by a water seal or equivalent device where it enters the lowermost zone of the furnace as for instance in my previous Patent No. 939,934, dated November 9, 1909, and also if necessary where it leaves the upper zolie.

Carbonaceous fuel may be introduced onto the uppermost hearth 7 of the lowermost zone of the furnace through a spout 24: from a hopper 25 by means of a screw conveyer 26 or other suitable device and finely divided carbonaceous material or other available reducing agent may be introduced by similar means onto the uppermost hearth 4 of the intermediate zone of the furnace in order to intensify the reducing action upon the material on the'hearths 4, 5 and 6, or, if desired, the hearths 7 8 and 9 may be abanw 126 doned and the reducing agent thus introduced upon the hearth 4 may be used to supply not only the reducing agent for the ma terial on the hearths 4:, 5 and 6 but also the gas for treating the sulfid in the uppermost zone of the furnace, or the gas generating function of the furnace may be entirely eliminated and both the reducing and sulfur vaporizing zones of the furnace may be supplied with gas derived froman independent generator.

The temperature in the treating zones of the furnace may be produced and maintained either in Whole or in part by the heat of the hearths, if the furnace is of the muffle type, or in Whole or in part by the high temperature of the introduced gas or by the partial combustion thereof.

Where a furnace of the zone type is used it is not essential that each zone should have a series of superposed hearths nor is it necessary that the zones shall be superposed in the same vertical plane, nor even that they shall be superposed at all, since my invention can also be carried out in a horizontal or slightly inclined furnace of the type of a rotary cement kiln, a strongly reducing flame such as that of water gas being introduced into the lower or discharging end of said furnace and passing through it from end to end, and the steam or other reagent being introduced at the receiving end of the furnace so as to provide for a supply of such reagent to the sulfid in the initial zone of the furnace, the elimination of the sulfur and the production of the oxid being effected in such initial zone and the conversion of the oxid to metallic form being effected in the following zone of the furnace.

In a furnace of this type the passage of the material through the furnace is effected by reason of the rotation of the furnace on an inclined axis, but mechanical means for effecting movement of the material can be dispensed with. If, for instance, the material is coarse or lumpy and of a permeable character it can be charged into a vertical kiln or oven fired at the bottom with a reducing flame and provided at an intermediate point with means for introducingsteam or other reagent.

The material passing down by gravity through such vertical furnace would, in the upper zone of the same, be so treated as to effect the elimination of the sulfur and the production of the metallic oxid and in the lower zone to efiect the reduction of such oxid to the metallic form, and if the necessary temperature is produced at the bottom of the furnace, as for example by means of a blast, associated with the sufficient amount of reducing agent, the metal might be delivered from the furnace in a molten condition.

My invention may also be carried out without resorting to the zone system of treatment or the zone system offurnace construction, for instance, the successive treatments described could be administered to a stationary mass of material or one stirred or agitated without being conveyed upon the single stationary or rotating horizontal hearth of a furnace.

Conducting the operation as a continuous process effects great saving in fuel since the high temperature gases, after performing their reducing function in the lower zone of the furnace, can be conveyed to the upper zone while they still retain heat enough for the proper performance of their function in said upper zone. The conduct of the process is also very flexible for instance if the proper elimination of sulfur and production of oxid cannot be efiected on the three hearths of the upper zone it may be continued or completed upon the uppermost hearth of the zone beneath and in order to compensate for thus depriving said lower zone of one of its hearths the operation can be slowed down or the quantity of reducing agent for acting upon the material on the remaining hearths of said lower zone can be increased, or there can be an increase in temperature, thus providing ample means for regulating the conduct of the process.

The strongly reducing condition necessary to be maintained in the lower zone of the furnace results in gases which have become less reducing or even neutral and these gases are therefore suitable for delivery to the upper zone where the atmosphere is not required to be strongly reducing. The ideal condition would be to generate a strongly reducing gas in the lowermost zone of the furnace which gas could be delivered at a very high temperature to the reducing or intermediate zone, and, after having performed its function therein and having lost to some extent its reducing character, could then be conveyed to the uppermost zone.

If, in consequence of decreased combustion in the gas producer zone of the furnace it is necessary to add heat to the intermediate or uppermost zone, or both, the mufiie construction readily permits of the application of such additional heat through the medium of the heating chambers of the hearths.

I claim:

1. The within described continuous process of producing metal from sulfur compounds containing the same, said process consisting in first subjecting the compound, at a temperature suflicient to vaporize the sulfur, to an atmosphere containing a reagent which will oxidize themetal without promoting the oxidation of the sulfur, and then continuing the subjection of the oxid thus formed to a reducing atmosphere at a temperature sufiicient to convert the oxid to metallic form.

2. The within described continuous proc 'ess of producing metal from sulfur compounds containing the same, said process consisting in passing the material progressively through a series of zones, sub ect1ng it in the initial zone, at a temperature suf- In testimony whereof, I have signed my ficient to vaporize the sulfur, to an atmosname to this specification, in the presence 1 phere containing a reagent which will of two subscribing witnesses.

oxidize the metal without promoting the o 5 oxidation of the sulfur, and, in later zone, UTLEY WEDGE subjecting the oxid thus formed to a reduc- Wltnessesz ing atmosphere at a'temperature suflicient KATE A. BEADLE,

to convert the oxid to metallic .form. HAMILTO D. TURNER. 

